webpack-bootstrap-ui-kit/src/html/_components/LoadingSpinner.html

<style>
  @keyframes lds-ellipsis1 {
    0% {
      transform: scale(0);
    }
    100% {
      transform: scale(1);
    }
  }
  @keyframes lds-ellipsis3 {
    0% {
      transform: scale(1);
    }
    100% {
      transform: scale(0);
    }
  }
  @keyframes lds-ellipsis2 {
    0% {
      transform: translate(0, 0);
    }
    100% {
      transform: translate(1.35rem, 0);
    }
  }
  body,
  html {
    font-size: 14px;
    margin: 0;
    padding: 0;
    background: #fff;
    color: #333;
    overflow-x: hidden;
  }
  @media (min-width: 2000px) {
    html,
    body {
      font-size: 0.9vw;
    }
  }
  #PageLoading {
    position: fixed;
    left: 0;
    top: 0;
    margin: 0;
    width: 100% !important;
    height: 100% !important;
    display: -ms-flexbox;
    display: flex;
    -ms-flex-align: center;
    align-items: center;
    -ms-flex-pack: center;
    justify-content: center;
    z-index: 2000;
    will-change: opacity;
    background: #212529;
    color: #212529;
  }
  #PageLoading .logo {
    filter: invert(1);
    margin-left: 20px;
    margin-left: 2vw;
    width: 100px;
    width: 12.5vw;
  }
  #PageLoading .tagline {
    color: #fff;
    font-size: 1.8rem;
    font-size: 4vh;
    letter-spacing: 0.25em;
  }
  .main-bn {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 99999999;
    padding: 0.5rem 1rem;
    text-align: center;
    color: #fff;
    background: #ff0000;
  }
  img,
  iframe {
    max-width: 100%;
  }
  .loading-spinner {
    text-align: center;
  }
  .lds-ellipsis {
    display: inline-block;
    position: relative;
    width: 4.57rem;
    height: 1rem;
    color: #fff;
  }
  .lds-ellipsis div {
    position: absolute;
    top: 0.15rem;
    width: 0.78rem;
    height: 0.78rem;
    border-radius: 50%;
    background: #888;
    animation-timing-function: cubic-bezier(0, 1, 1, 0);
  }
  .lds-ellipsis div:nth-child(1) {
    left: 0.42rem;
    animation: lds-ellipsis1 0.6s infinite;
  }
  .lds-ellipsis div:nth-child(2) {
    left: 0.9rem;
    animation: lds-ellipsis2 0.6s infinite;
  }
  .lds-ellipsis div:nth-child(3) {
    left: 1.85rem;
    animation: lds-ellipsis2 0.6s infinite;
  }
  .lds-ellipsis div:nth-child(4) {
    left: 3.21rem;
    animation: lds-ellipsis3 0.6s infinite;
  }
  @keyframes lds-text {
    from {
      font-size: 1em;
    }
    to {
      font-size: 1.5em;
    }
  }
  .lds-text {
    position: absolute;
    top: 50%;
    left: 50%;
    margin-left: -5rem;
    margin-top: 8rem;
    font-size: 0.8rem;
    letter-spacing: 0.25em;
    color: #fff;
  }
  .lds-text b {
    font-weight: 300;
    animation: lds-text 5s ease infinite alternate;
  }
  .lds-text b:nth-child(1) {
    animation-delay: 0.5s;
  }
  .lds-text b:nth-child(2) {
    animation-delay: 1s;
  }
  .lds-text b:nth-child(3) {
    animation-delay: 1.5s;
  }
  .lds-text b:nth-child(4) {
    animation-delay: 2s;
  }
  .lds-text b:nth-child(5) {
    animation-delay: 2.5s;
  }
  .lds-text b:nth-child(6) {
    animation-delay: 3s;
  }
  .lds-text b:nth-child(7) {
    animation-delay: 3.5s;
  }
  .lds-text b:nth-child(8) {
    animation-delay: 4s;
  }
  .lds-text b:nth-child(9) {
    animation-delay: 4.5s;
  }
  .lds-text b:nth-child(10) {
    animation-delay: 5s;
  }
  @media (orientation: portrait) {
    #PageLoading .logo {
      width: 50vw;
    }
    #PageLoading .tagline {
      font-size: 4vw;
    }
  }
</style>

<div id="PageLoading">
  <div class="loading-spinner">
    <img class="logo" src="../../img/logo.svg" width="200" alt="UI Kit" /><br />
    <div class="lds-ellipsis">
      <div></div>
      <div></div>
      <div></div>
      <div></div>
    </div>
    <br />
    <div class="lds-placeholder">LOADING...</div>
    <div class="lds-text">
      <b>L</b>
      <b>O</b>
      <b>A</b>
      <b>D</b>
      <b>I</b>
      <b>N</b>
      <b>G</b>
      <b>.</b>
      <b>.</b>
      <b>.</b>
    </div>
  </div>
</div>